1. Field of the Invention
The present invention relates to a technology to enable networked terminal devices to access a shared folder located on a computer such as a server.
2. Description of the Related Art
Technologies for sharing folders located on a computer on a network with multiple other computers have been proposed in the conventional art.
According to the system described in Japanese Laid-Open Patent Application No. 2003-15882, for example, each user, using a networked client computer, can access a shared folder on a server and run programs stored in this shared folder. This type of system is generally termed a ‘client-server network’. With a client-server network, if a shared folder is created for each user on the server, users can store their individual data on the server.
In Japanese Laid-Open Patent Application Nos. 2003-5937 and 2001-175387, a system is described whereby documents located on any of multiple networked devices can be shared by any such device. This type of system is generally called a ‘peer-to-peer network’.
In a peer-to-peer network, when a user's own terminal device is powered off, or when it is not connected to the network, the files stored on that terminal device cannot be used by other users. Therefore, the problem of other users accessing the user's own files on the user's terminal device without the user's knowledge while the user is not operating the terminal device is of little concern.
However, a peer-to-peer network is not suitable for a large-scale network system. Furthermore, in order for a folder on a terminal device to be shared, the terminal device must be equipped with a server function. Therefore, such a network is not suitable for small-scale terminal devices such as a PDAs (Personal Digital Assistants) or cellular telephones.
On the other hand, because all documents are centrally managed from the server in a client-server network, such a network is well suited for management of users' shared folders in a large-scale system.
However, in a client-server network, the contents of a user's shared folder (e.g. data) can be accessed by others without the user's knowledge, regardless of whether the user is operating the terminal device.
In another approach, a file can be sent and received by email. However, if the file is large, the email server may refuse to accept the file, making this approach unsuitable for file sharing on a consistent basis.